The control unit continuously compares each up/down shift against a corresponding "ideal" up/down shift pattern. Two algorithms are used to reach this ideal pattern for each shift: Fast adaptive and slow adaptive. If the difference between a real shift and the ideal pattern is significant, the fast adaptive logic is used. If the difference between a real shift and the ideal pattern is small, the slow adaptive logic is used. This function resets all the shift adaptive data and force the control unit to use the fast adaptive algorithm.